Combustion apparatus

ABSTRACT

In a combustion apparatus that includes a combustion plate having a burner frame with a shape of a picture frame, which covers an open surface of a burner body, and a frame flange part outwardly extending from a side plate part, which is sandwiched between a body flange part of the burner body and a box flange part of a combustion box, which is fastened to the body flange part, a projecting part(s) positioning the burner frame with respect to the combustion box, which comes into contact with, or comes close to and is disposed opposite to an inner surface of the combustion box is provided with the side plate part of the burner frame. Preferably, the projecting part(s) is provided at a portion away from an end of a side of an opening peripheral edge part of the side plate part to a side of the frame flange part.

TECHNICAL FIELD

The invention relates to a combustion apparatus that includes a burner constituted by a burner body an inside of which an air-fuel mixture is supplied to and a combustion plate covering an open surface of the burner body, and a combustion box having, at an end, a box flange part which is fastened to a body flange part enclosing the open surface of the burner body.

BACKGROUND ART

Conventionally, as this kind of the combustion apparatus, there has been known the combustion apparatus that uses the combustion plate having a burner frame with a shape of a picture frame and an air-fuel mixture permeable body covering an opening enclosed by the burner frame from a burner-body side, through which the air-fuel mixture permeates, so that the air-fuel mixture permeating the air-fuel mixture permeable body and ejecting from the opening combusts in the combustion box (See Patent document No. 1, for example). In this combustion apparatus, the burner frame has an opening peripheral edge part around the opening, a side plate part bending from the opening peripheral edge part to the burner-body side, and a frame flange part outwardly extending from an end of the burner-body side of the side plate part and being sandwiched between the body flange part and the box flange part.

Here, in the conventional combustion apparatus, the side plate part of the burner frame is so far away from an inner surface of the combustion box. Therefore, a width of a portion of the frame flange part of the burner frame, which faces to the inner space of the combustion box, becomes broad. Then, a heat insulation material covering the portion of the frame flange part, which faces to the inner space of the combustion box, is provided so that overheat of the burner frame due to heat input of radiant heat from flames to the portion can be suppressed. The heat insulation material is held by a stationary plate fitted to the frame flange part. Additionally, a protrusion(s) for positioning, which comes into contact with, or comes close to and is disposed opposite to the inner surface of the combustion box is provided with the stationary plate and the combustion plate is positioned with respect to the combustion box. In this connection, positioning of the combustion plate with respect to the combustion box is for suppressing that the flames come too close to the inner surface of the combustion box and preventing the combustion box from being overheated.

Incidentally, in recent, the combustion plate of which a distance between the side plate part of the burner frame and the inner surface of the combustion box is relatively shorted has been developed. In the combustion apparatus using such the combustion plate, a width of the portion of the frame flange part of the burner frame, which faces to the inner space of the combustion box, becomes narrow, even by not covering the portion with the heat insulation material, overheat of the burner frame can be suppressed. In this case, it is unnecessary to fit the stationary plate for the heat insulation material to the frame flange part. However, if omitting the stationary plate, positioning of the combustion plate with respect to the combustion box by such the protrusion(s) for positioning as is provided with the stationary plate in the conventional combustion apparatus will not be able to be accomplished.

REFERENCE

Patent document No. 1: JPA 2017-116160

SUMMARY OF INVENTION Technical Problem

In the light of the above-mentioned problem, an object of the invention is that positioning of the combustion plate with respect to the combustion box is possible even in a combustion apparatus which omits the stationary plate for the insulation material, which has been fitted to the frame flange part.

Solution to Problem

In order to accomplish the object, the invention presupposes a combustion apparatus that includes a burner constituted by a burner body an inside of which an air-fuel mixture is supplied to and a combustion plate covering an open surface of the burner body; and a combustion box having, at an end, a box flange part that is fastened to a body flange part enclosing the open surface of the burner body, wherein the combustion plate has a burner frame with a shape of a picture frame and an air-fuel mixture permeable body covering an opening enclosed by the burner frame from a burner-body side, through which the air-fuel mixture permeates, and wherein the burner frame has an opening peripheral edge part around the opening, a side plate part bending from the opening peripheral edge part to the burner-body side, and a frame flange part outwardly extending from an end of the burner-body side of the side plate part and being sandwiched between the body flange part and the box flange part. In the combustion apparatus of the invention, a projecting part(s) positioning the burner frame with respect to the combustion box, which comes into contact with, or comes close to and is disposed opposite to an inner surface of the combustion box is provided with the side plate part of the burner frame.

According to the invention, positioning of the burner frame, i.e., the combustion plate, can be accomplished by the projecting part(s) provided with the side plate part of the burner frame. Accordingly, even in the combustion apparatus omitting the stationary plate for the heat insulation material that has been fitted to the frame flange part, positioning of the combustion plate with respect to the combustion box is possible and overheat of the combustion box can be prevented.

Additionally, in the invention, it is desirable that the projecting part(s) is provided at a portion that is away from an end of a side of the opening peripheral edge part of the side plate part to a side of the frame flange part. According to this, the projecting part(s) is away from flames formed by combustion of the air-fuel mixture permeating the air-fuel mixture permeable body and ejecting from the opening to a burner-body side. Therefore, heat input of radial heat from the flames to the projecting part(s) is suppressed. As a result, temperature rise of the combustion box due to heat transfer to the combustion box through the projecting part(s) can be suppressed.

Further, in the invention, it is desirable that the projecting part(s) is provided with only a plurality of portions of the side plate part, which are separated in a circumferential direction. According to this, being different from a manner in which the projecting part is provided over an entire circumference of the side plate part, heat transfer area from the projecting part(s) to the combustion box decreases. Therefore, temperature rise of the combustion box due to heat transfer to the combustion box through the projecting parts can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a combustion apparatus of an embodiment of the invention.

FIG. 2 is a perspective view of the combustion apparatus seen from an opposite side with respect to FIG. 1 .

FIG. 3 is a sectional view that is cut off along a line of FIG. 1 .

FIG. 4 is a sectional view that is cut off along a IV-IV line of FIG. 3 .

FIG. 5 is a perspective view of a combustion plate of a burner in a decomposed state, which is a component of the combustion apparatus of the embodiment.

FIG. 6 is a bottom view of the above-mentioned combustion plate in an assembled state, which is seen from below.

FIG. 7A is an enlarged sectional view of a main part, which is cut off along a VIIa-VIIa line of FIG. 6 , of the assembled state of the combustion apparatus and FIG. 7B is an enlarged sectional view of the main part, which is cut off along a VIIb-VIIb line of FIG. 6 , of the assembled state of the combustion apparatus.

DESCRIPTION OF EMBODIMENTS

A combustion apparatus, which is shown in FIGS. 1 through 4 , of an embodiment of the invention includes a totally-aerated burner 1 that is constituted by a burner body 11 an inside of which an air-fuel mixture (a mixed gas of a fuel gas and a primary air) is supplied to and a combustion plate 12 covering a downward open surface 111 of the burner body 11, and a combustion box 2 having, at an upper end, a box flange part 22 fastened by a screw 21 to a body flange part 112 enclosing the open surface 111 of the burner body 11. In the combustion box 2, a heat exchanger 3 for hot-water supply is housed.

The heat exchanger 3 is constituted by a fin-tube type heat exchanger that includes a plurality of fins 31 and a plurality of heat-absorbing tubes 32 piercing the fins 31. At an outside of each of side plates 23, 24 of one side and the other side in lateral direction, of the combustion box 2, a plurality of U-shaped vent pipes 33 connecting adjacent two heat-absorbing tubes 32, 32 are provided and all of the heat-absorbing tubes 32 are connected in series. A pipe 34 with which a water inlet 34 a is provided at an end portion is connected to the heat-absorbing tube 30 at an upstream end.

Referring to FIG. 4 , at an inside of a portion of a side plate 25 of a front side of the combustion box 2, which is positioned above the heat exchanger 3, three water passages, i.e., a first water passage 4 ₁, a fifth water passage 4 ₅, and a ninth water passage 4 ₉, which consist of a pipe, are disposed in sequence from below so as to come into contact with the side plate 25. Also, at an inside of a portion of a side plate 26 of a rear side of the combustion box 2, which is positioned above the heat exchanger 3, three water passages, i.e., a third water passage 4 ₃, a seventh water passage 4 ₇, and an eleventh water passage 4 ₁₁, which consist of a pipe, are disposed in sequence from below so as to come into contact with the side plate 26. Additionally, at an outside of the side plate 23 of one side in the lateral direction of the combustion box 2, as shown in FIGS. 1, 3 , a connecting pipe connecting the heat-absorbing tube 32 at a downstream end of the heat exchanger 3 to the first water passage 4 ₁ is provided and at a portion of the side plate 23, which is positioned above the heat exchanger 3, a fourth water passage 4 ₄ connecting the third water passage 4 ₃ and the fifth water passage 4 ₅, an eighth water passage 4 ₈ connecting the seventh water passage 4 ₇ and the nineth water passage 4 ₉, and a twelfth water passage 4 ₁₂ connected to the eleventh water passage 4 ₁₁ are provided. Further, with the side plate 24 of the other side in the lateral direction of the combustion box 2, as shown in FIGS. 2, 3 , a second water passage 4 ₂ connecting the first water passage 4 ₁ and the third water passage 4 ₃, a sixth water passage 4 ₆ connecting the fifth water passage 4 ₅ and the seventh water passage 4 ₇, and a tenth water passage 4 ₁₀ connecting the nineth water passage 4 ₉ and the eleventh water passage 4 ₁₁, each of which is positioned above the heat exchanger 3, are provided. Each of the second, sixth, and tenth water passages 4 ₂, 4 ₆, 4 ₁₀, and each of the fourth, eighth, and twelfth water passages 4 ₄, 4 ₈, 4 ₁₂ are constituted by cavities inward in the lateral direction, which are formed at each of the side plates 24, 23, and lids 41 fitted to an outside surface of each of the side plates 24, 23 so as to cover the cavities. Water heated in the heat exchanger 3 flows in the first water passage 4 ₁ through the twelfth water passage 4 ₁₂ in sequence and are supplied from a hot water outlet 42 provided with an end portion of the twelfth water passage 4 ₁₂ to a hot water pipe, not shown, connecting to the hot water outlet 42. Then, each of the side plates 23 through the side plate 26 of the combustion box 2 are configured to be cooled by water flowing in the first water passage 4 ₁ through the twelfth water passage 4 ₁₂.

Furthermore, on the side plate 25 of the front side of the combustion box 2, electrode parts 5 having an ignition electrode 51, a grounding electrode 52, and a pair of flame rods 53, 53 which pierce a side-plate portion between the fifth water passage 4 ₅ and the nineth water passage 4 ₉ and protrude in the combustion box 2, are mounted. In this connection, with the electrode parts 5, an inspection window 54 through which visual inspect in the combustion box 2 is possible is additionally provided.

Next, detailed explanation regarding the burner 1 will be made. At the burner body 11, an inlet port 113, to which a not-shown fan that supplies the air-fuel mixture is connected, is opened. On the inlet port 113, a check valve 13 that prevents the air-fuel mixture remaining in the burner body 11 at time of stopping the fan from flowing backward to a side of the fan is mounted.

With reference also to FIG. 5 , a combustion plate 12 has a burner frame 121 with a shape of a picture frame and an air-fuel mixture permeable body 123 covering an opening 122 enclosed by the burner frame 121 from a burner-body 11 side (from above), through which the air-fuel mixture permeates. The air-fuel mixture permeable body 123 can be constituted by woven or nonwoven fabric of a heat-resistant fiber such as a metal fiber and the like, or a porous sintered compact and the like. On a rear surface (upper surface), which is a surface of an upstream side in a flowing direction of the air-fuel mixture, of the air-fuel mixture permeable body 123, a distribution plate 124 in which a plurality of distribution holes 124 a are formed is overlapped. Then, the air-fuel mixture supplied in the burner body 11 ejects from the opening 122 through the distribution holes 124 a and the air-fuel mixture permeable body 123, and totally aerated combustion (combustion unnecessary for secondary air) is performed. In this connection, a sectional shape along a front-to-back direction of the opening 122, as shown in FIG. 4 , curves into an arcuate shape and the sectional shapes of the air-fuel mixture permeable body 123 and the distribution plate 124 similarly curves into the arcuate shape along the front-to-back direction.

The burner frame 121 has an opening peripheral edge part 1211 around the opening 122, a side plate part 1212 bending from the opening peripheral edge part 1211 to the burner-body 11 side (upward), and a frame flange part 1213 outwardly extending from an upper end of the side plate part 1212. With a portion of the opening peripheral edge part 1211, which is close to an inner circumference, a squeezed part 1211 a that comes down by one step is provided. A peripheral edge part of the air-fuel mixture permeable body 123 is overlapped on the squeezed part 1211 a. In a state where the distribution plate 124 is overlapped on the rear surface of the air-fuel mixture permeable body 123, the combustion plate 12 is assembled by spot-welding a peripheral part of the distribution plate 124 to a portion of the opening peripheral part 1211 of an outside of the squeezed part 1211 a at a constant distance. The frame flange part 1213 is sandwiched between the body flange part 112 and the box flange part 22. Additionally, a packing 6 is interposed between the frame flange part 1213 and the body flange part 112 and a sealing property between the burner body 11 and the combustion plate 12 is secured. In this connection, the packing 6, as clearly shown in FIG. 7 , has a portion 61 outwardly extending beyond the frame flange part 1213. This portion 61 is interposed between the body flange part 112 and the box flange part 22 and the sealing property between the body flange part 112 and the box flange part 22 is secured.

Here, in the embodiment, a distance between the side plate part 1212 of the burner flame 121 and an inner surface of the combustion box 2, i.e., an inner surface of each of the side plates 23, 24, 25, 26, is short. Therefore, a width of a portion, which faces to an inner space of the combustion box 2, of the frame flange part 1213 of the burner frame 121 becomes narrow. As a result, even though this portion is not covered by a heat insulation material, overheat of the burner frame 121 will be able to be suppressed. Accordingly, a stationary plate for the heat insulation material, which has been conventionally provided with the frame flange part 1213, can be omitted. On the other hand, in the case where the stationary plate is omitted, a positioning function of the combustion plate 12 with respect to the combustion box 2 by the protrusion(s) for positioning, which has been provided with the stationary plate, cannot be obtained.

Then, in the embodiment, projecting parts 1214 positioning the burner frame 121 with respect to the combustion box 2, which come close to and are disposed opposite to the inner surface of the combustion box 2, are provided with the side plate part 1212 of the burner frame 121. According to this, by the projecting parts 1214, the burner frame 121, i.e., the combustion plate 12, with respect to the combustion box 2 can be positioned. Consequently, even in the combustion apparatus, the stationary plate for the heat insulation material, which has been provided with the frame flange part 1213, is omitted, the combustion plate 12 will be positioned with respect to the combustion box 2 and it will be possible that overheat of the combustion box 2 is prevented.

In this connection, the projecting parts 1214 are provided with only a plurality of portions of the side plate part 1212, which are separated in a circumferential direction. Specifically explaining, with reference also to FIGS. 6, 7 , not only the projecting parts 1214 of #1 that come close to and are disposed opposite to inner surfaces of the side plates 23, 24 positioned at each side in a lateral direction of the combustion box 2 are provided with central parts in a front-to-back direction of portions of the side plate parts 1212, which are positioned at both sides in a lateral direction of the burner frame 121, but also the projecting parts 1214 of #2 that come close to and are disposed opposite to the inner faces of the side plates 25, 26 positioned at each of the front-to-back sides are provided with both end parts in the lateral direction of portions of the side plate part 1212, which are positioned at both sides in the front-to-back direction of the burner frame 121. According to this, being different from a manner in which the projecting parts 1214 are provided over an entire circumference of the side plate part 1212, heat transfer area from the projecting parts 1214 to the combustion box 2 decreases. Therefore, temperature rise of the combustion box 2 due to heat transfer to the combustion box 2 through the projecting parts 1214 can be suppressed.

Additionally, in the embodiment, each of the projecting parts 1214 is provided with a portion that is away from an end of a side of the opening peripheral edge part 1211 of the side plate part 1212 to the frame-flange 1213 side. According to this, the projecting parts 1214 are away from flames formed by the combustion of the air-fuel mixture ejecting from the opening 122 to the burner-body 11 side. Therefore, heat input of radial heat from the flames to the projecting parts 1214 is suppressed. As a result, temperature rise of the combustion box 2 due to heat transfer to the combustion box 2 through the projecting parts 1214 can be more effectively suppressed.

Though the embodiment of the invention is explained with reference to the drawings in the above, the invention is not limited to the embodiment. For example, in the above-mentioned embodiment, though each of the projecting parts 1214 comes close to and is disposed opposite to each of the inner surfaces of the combustion box 2, each of the projecting parts 1214 can be provided so as to come into contact with each of the inner surfaces of the combustion box 2. Additionally, though the open surface 111 of the burner body 11 of the burner 1 in the above-mentioned embodiment is disposed so as to direct downward, the invention is applicable to a combustion apparatus in which the burner body 11 is disposed in such a manner as the open surface 111 directs upward.

EXPLANATION OF SYMBOLS

-   -   1 Burner     -   11 Burner body     -   111 Open surface     -   112 Body flange part     -   12 Combustion plate     -   121 Buner frame     -   1211 Opening peripheral edge part     -   1212 Side plate part     -   1213 Frame flange part     -   1214 Projecting part(s)     -   122 Opening     -   123 Air-fuel mixture permeable body     -   2 Combustion box     -   22 Box flange part 

What is claimed is:
 1. A combustion apparatus comprising, a burner constituted by a burner body an inside of which an air-fuel mixture is supplied to and a combustion plate covering an open surface of the burner body; and a combustion box having, at an end, a box flange part that is fastened to a body flange part enclosing the open surface of the burner body, wherein the combustion plate has a burner frame with a shape of a picture frame and an air-fuel mixture permeable body covering an opening enclosed by the burner frame from a burner-body side, through which the air-fuel mixture permeates, and wherein the burner frame has an opening peripheral edge part around the opening, a side plate part bending from the opening peripheral edge part to the burner-body side, and a frame flange part outwardly extending from an end of the burner-body side of the side plate part and being sandwiched between the body flange part and the box flange part, wherein: a projecting part(s) positioning the burner frame with respect to the combustion box, which comes into contact with, or comes close to and is disposed opposite to an inner surface of the combustion box is provided with the side plate part of the burner frame.
 2. The combustion apparatus as claimed in claim 1, wherein the projecting part(s) is provided at a portion that is away from an end of a side of the opening peripheral edge part of the side plate part to a side of the frame flange part.
 3. The combustion apparatus as claimed in claim 1, wherein the projecting part(s) is provided with only a plurality of portions of the side plate part, which are separated in a circumferential direction.
 4. The combustion apparatus as claimed in claim 2, wherein the projecting part(s) is provided with only a plurality of portions of the side plate part, which are separated in a circumferential direction. 